Re: [Bridge] bridge interface mac address

[Sergei Zhirikov <sfzhi@yahoo.com>]

On 2010-09-08 12:28, x@muc.ccc.de wrote:
> hi!
>
> i'm using dynamips (router/switch emulator) and would like to have an interface on the host as a link to the 'emulated lab'. with dynamips, one of the host's interfaces can be used to connect to a port of the 'emulated lab'. dynamips obviously injects its packets into this interface, and sniffs for packets directed towards the 'emulated lab'.
>
> now i just have a single physical interface on the host. and i don't want the lab-traffic to pass thru the physical interface (and productive segment connected to it).
> so i thought hey, let's be clever, just create a bridge. we don't need any bridge-members (yet), we just want to use it for the dynamips link for now.
>
> after a brctl addbr, i get a bridge-interface - with a mac of 00:00:00:00:00:00.
> tried it anyway: it doesn't work (i see arp-requests from the host, i see arp-replies to the host - which the host obviously simply ignores, most probably because of the all-zero-mac).
> turns out it's also not possible to change the mac - not even to a locally administered mac.
>
> is there a special way to set the bridge's mac? actually i find it quite irritating that it's not simply possible to change it just like with any other interface!?
>
> also i think it might not be wise to treat 00:00:00:00:00:00 special, filter it, or similar (after all it's a valid global unicast mac - assigned to xerox...).
>
> regards,
>
> 	Chris

A bridge without a bridge? Why?
If you just need a dummy network interface there is a driver called "dummy", which is meant exactly for that, and it's included in standard Linux.